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'Everything that's happening now is normal' — GNS says aftershocks following East Cape quakes are expected

Since yesterday’s 7.2 magnitude earthquake off the coast of East Cape, there have been about 140 smaller aftershocks in the region. But, GNS Science says that’s no cause for concern.

Source: Breakfast

“After a large earthquake, such as the magnitude 7.2 East Cape event, we expect for there to be further earthquakes in the region, some of which may be widely felt,” GNS Science Seismologist Dr Matt Gerstenberger says.

“The most likely scenario over the next 30 days is that further quakes of smaller magnitude will occur, becoming less frequent."

However, due to the increased activity in the area there is still increased probabilities of larger events. People should stay vigilant about the threat of another large earthquake or tsunami.

Since the magnitude 7.2 East Cape event there have been more than 140 earthquakes of magnitude 4 or higher recorded in the region. The largest recorded earthquake since the mainshock was a magnitude 6.1 that occurred just after 1pm today.

“The main message is that everything that’s happening now is normal, if anything it’s a fewer amount of aftershocks,” Gerstenberger says.

“Even though it’s still decaying away so far we can expect there will be other felt earthquakes.”

There were more than 52,000 "felt" reports of yesterday’s magnitude 7.2 quake on the Geonet website.

After the magnitude 7.2 hit off the east coast of the North Island yesterday, a few hours later there was a magnitude 7.4 and magnitude 8.1 earthquake in the Kermadecs.

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The latter quakes triggered tsunami warnings and evacuations in Northland, Gisborne and some Bay of Plenty towns.

Following those events, GeoNet also developed three scenarios for what earthquakes may happen over the next 30 days based on forecast models.

The most likely scenario is that further earthquakes of a smaller magnitude will decrease in frequency over the next 30 days.